Electronic recording of Point Of Sale (POS) transactions is well-known in the art. However, POS transactions of the type involving a human signature, such as those requesting extension of credit, have required a large amount of storage to capture the human signature in electronic form. The large amount of storage required for a signature signal is acceptable in certain industries where the transaction volume is low. For example, in the package delivery industry where a human signature is recorded along with the delivery of a package, the human signature is converted into an electronic signal which is recorded and stored.
However, in POS transactions involving requests for credit extension where a large number of transactions are involved, the storage requirement for record signals, each comprised of a signature signal and a transaction signal, becomes enormous.
Modified ring encoding is one of the techniques that has been used to encode weather maps, contour maps and other pictorial line-drawings. See, for example, "A Rate And Distortion Analysis Of Chain Codes For Line Drawings" by David L. Neuhoff and Kenneth G. Castor, IEEE Transactions On Information Theory, Vol. IT-31, No. 1, January 1985. However, the application of the modified ring-encoding technique to signature compression in a manner to store signature signals in a well-defined bit field has not been known heretofore.